Problem Based Learning (PBL) has been adopted in educational programs in a variety of disciplines, including veterinary medicine. There is a voluminous literature on the subject, but it often remains unclear just what is being done in the name of PBL, and different accounts highlight different, often contradictory, positions on the key features of the approach. Similarly, despite the many claims made for the advantages of PBL, the evidentiary basis of such claims is often questionable. This article provides an introductory overview of what appear to be the key features of the approach and a brief summary of empirical evidence on its effectiveness.